The purpose of this study is to compare the effects of gradual and abrupt smoking cessation techniques, when smoking behavior prior to quitting is based on an interval or ad lib schedule. Smoking cessation programs could have a significant impact on the cardiovascular and neoplastic disease rates. However, the smoking cessation process is poorly understood. With a few exceptions, our treatments inadequately account for both the psychological and pharmacological properties of smoking. Long- term cessation rates may be improved if the treatment: (a) Prohibits the smoker from manipulating nicotine dose in order to achieve a desired change in affect or sensorium; (b) reduces the saliency of the environmental cues associated with these effects; (c) manages acute urges and withdrawal symptoms; (d) promotes intervention in a relapse prone situation. The gradual reduction and interval smoking program piloted in our laboratory strives to fulfill these goals and this study is designed to assess it's key elements. Initial results suggests the program is as effective as the best of current treatments. Further investigation seems warranted to determine: (a) The independent and interactive effects of gradual or abrupt cessation; and interval or ad lib smoking schedules; (b) The relative contribution of these procedures to a behavioral program of urge control and relapse prevention. One hundred eighty smokers, blocked on cotinine levels, will be randomly assigned to four treatment conditions: gradual reduction of cigarettes/ad lib smoking schedule prior to quitting; gradual reduction/interval smoking schedule; abrupt cessation/ad lib schedule; abrupt cessation/interval schedule. Cessation takes place over the first 3 weeks as follows: Gradual reduction/interval smoking involves progressive reductions in smoking frequency and increases in intra cigarette interval; in abrupt/interval smoking, a fixed time is set between cigarettes, but consumption frequency does not change; In gradual/ad lib, consumption is progressively reduced without a systematic manipulation of the smoking schedule; abrupt/ad lib have no reduction goals or schedule; All groups quit on the same target date and receive 8 weeks of concurrent training in cognitive behavior modification and relapse prevention. Abstinence will be biochemically verified and treatment compliance will be carefully monitored. Abstainers and nonabstainers will be examined for baseline and treatment differences in cotinine, mood, symptoms of withdrawal, reasons for smoking, self-efficacy, and post quitting frequency of use of nonsmoking coping behaviors.